I wouldn't be surprised if the problems were a consequence of poor record-keeping / handover by Xchange. When I returned the car, the dealer phoned Xchange to tell them that the car had been returned. While he was on the phone to them, he passed me the phone and told me that Xchange wanted to speak to me to confirm that I had returned the car, so I did.
However, knowing that Xchange was a useless as Uber with driver data and record-keeping, before I left the parking lot I phoned Xchange to check that their records had been updated properly and the support agent told me that no, there was no record of me having returned the car and that "the system" still showed me as being in possession of the car and that another payment was due the following week. So back into the dealership I went, and we repeated the entire process of the dealer phoning Xchange, passing the phone to me etc etc.
I went back out into the parking lot and phoned again. I spoke to a different agent and just asked when the next payment was due on my account. "No", the agent said, "The system is showing that you have already returned your car and this account is now closed".
"Perfect", I said, and ended the call.
A year before that, I had an Xchange rep literally yelling at me down the phone, claiming that because they had not yet received paperwork from the dealer when I got the car from him, there was no rental agreement in place, that I was in illegal possession of the car and that I could be stopped by the police and arrested and the car seized.
It became clear in that moment that Xchange were rank amateurs and that extreme care would be needed with them.
